Greece’s austerity referendum has put its battered economy and banks in eurozone limbo. Markets will be jarred by the uncertainty.

The weekend’s dramatic decision by the Greek government to call a July 5 referendum on whether to accept spending cuts and tax rises proposed by creditors has already had huge consequences, including the closure of Greek banks Monday. So much uncertainty is likely to jolt markets, which have been remarkably resilient to the latest flare-up in Greece’s long-running crisis.